Method of treating artificial silk cakes made by the spinning can process



Patented Oct. 6, 193i 'rED STATES PATENT OFFICE HUGO KIITTNER, OF DRESDEN, GERMANY, ASSIGNOR TO KUTTNER AKTIENGESELL- SCHAFT, OF PIRNA-ON-TI-IE-ELBE, GERMANY METHOD OF TREATING ARTIFICIAL SILK CAKES MADE BY THE SPINNING CAN PROCESS No Drawing. Application filed October 23, 1928, Serial No. 314,547, and in Germany November 5, 1927.

In carrying out the process disclosed in my prior specification Serial Number 260,396 Patent N 0. 1,708,583 it has been found that it is preferable and is connected with special technical advantages if the further treatment of the flattened and subsequently rinsed cakes prepared as set forth in my said prior specification is also extended to the drying of the cakes, so that the cake form is only abandoned by unwinding, and reeling or spooling the thread, after the completion of the drying. Hence only after the drying is finished does the cake receive internal support from the reel which carries it during the unwinding of the thread. This treatment has not given rise to any objections on the ground of the layers of thread becoming disarranged, but it is possible for the sake of precaution to bind the cake round with a thread before collapsing the reel, as is done in the case of yarn hanks.

It has been found specially advantageous for the thread to be first dried in the form of a thread cake in an entirely free, unstressed condition, so that it does not have to undergo any tension or any stress either owing to any internal sup-porting of the cake or owing to the unwinding and reeling or spooling before drying. Contrary to what might have been expected, the thread dried in an unsupported and unstressed condition remains completely smooth and unwaved, close in itself and therefore soft to the touch, whereas a thread dried in a stressed condition or after being stressed, even if only temporarily, exhibits the known waviness with which is ordinarily associated the occurrence of loose places in the thread, that is, the occurrence of places at which the individual fibres forming the entire thread do not lie close together.

Even when the thread thus dried subsequently has to be moistened once more for any reason, and therefore already has behind it the tension associated with the reeling or spooling after the first drying, that no longer perceptibly impairs the thread. Apart from this remoistening of the thread for the purpose of any subsequent treatment, which indeed only seldom comes into consideration, the finishing of the thread, including the drying, in the form of a cake, also presents advantages as regards the simplification of the production.

Finally the uniformity of the state of tension of the thread dried in the form of a cake is to be emphasized. By the expression state of tension, is here meant that the dried threaddoes not comprise portions which have undergone tensions differing from one another and which therefore exhibit different degrees of extensibility at rupture. If for example the thread unwound from the damp cake is dried on a reel, individual turns are unavoidably more heavily stressed on the reel, and in particular the inner turns bearing directly upon the point of support, are stressed more than the outer turns. Since according to the invention the thread is dried without any stress at all, it cannot contain portions of different stress conditions.

The drying of the cakes is preferably effected on hurdles. I

WVhat I claim is 1. A process for the additional treatment of cakes of artificial silk manufactured by the known spinning can process of pressing the cakes flat and rinsing them, said treatment consisting in thereupon drying the cakes without tension while still in the form of cakes and without any inner support of the annular filament layers, before unwinding and reeling the silk thread.

2. A process for the additional treatment of cakes of artificial silk that have been manufactured by the spinning can process and pressed fiat and rinsed by the method disclosed in U. S. Patent No. 1,708,583, said I treatment comprising the steps of drying the silk without tension while it is still in the form of cakes and without the assistance of any inner support of the annular filament layers.

In testimony whereof I have signed my name to this specification.

HUGO KUTTNER. 

